The present invention relates to an improved process for the preparation of p-hydroxybenzoic acid. More particularly, the invention relates to an improved process for the preparation of p-hydroxybenzoic acid from p-methoxytoluene in high yield by oxidizing p-methoxytoluene to p-anisic acid and cleaving the methyl ether to form p-hydroxybenzoic acid.
p-Hydroxybenzoic acid is an important precursor for the preparation of p-acetoxybenzoic acid. p-Acetoxybenzoic acid is prepared from p-hydroxybenzoic acid by esterification of the hydroxy group with acetic acid or acetic anhydride. The acetylation step is normally quantitative, after the p-hydroxybenzoic acid has been purified, usually by crystallization. The purified p-acetoxybenzoic acid is an important monomer for production of liquid catalyst copolymers.